A variety of electrical plugs have been designed to act as either a male or female plug. The trend has been to move from designs where the user could change gender to designs where the manufacturer established the gender and it could not, thereafter, be changed. Typical references which show this trend are:
U.S. Pat. No. 1,516,581 issued to Seufert. The plug has two female receptacles in its front end which are threaded for a small distance at the bottom of the female electrical contacts. The male electrical contacts, which are normally stored in recepticles in the rear of the plug, are screwed into the female receptacles when it is desired to convert the plug to the male state.
U.S. Pat. No. 2,538,296 issued to Crocker. A household electrical plug is taught which has retractable male contacts. The plug is made up of a hollow shell which is flat on two sides, has a hole for the usual household electrical cord at its rear, and two holes for the usual flat male contacts at its front end. The electrical cord conductors connect to two metal spring contacts which extend along the inner sides and length of the plug. The contacts are curved inward at their forward ends. The male contacts are attached to a positioning "slide" at their rear end. The curved edges of the springs fit a concavity to lock the male contacts in the forward position. When the male contacts are retracted, i.e., in the female position, the springs along the side act as the female contacts when a male plug is inserted.
U.S. Pat. No. 2,796,591 issued to Carter et al. In this household plug, two conductors in a cord pass through a piston-shaped element positioned within a round plug. The conductors are attached to two flat male electrical contacts which are imbedded in the front of the piston. The piston is locked in a forward or rear position to achieve the desired gender.
The above patents teach the art wherein the user can adapt a plug as needed. This art required complex manufacturing processes, close tolerance fittings and large part inventories. The following art shows the trend to reduce the number of parts and the number of steps required to form and assemble the parts and plugs.
U.S. Pat. No. 3,083,344 issued to Long. An all-purpose plug is taught which can be used in its male form, in a female form, and as a connector between two cord ends. When used as a plug, a home electrical cord is attached to metal springs which have been performed to fit around positioning elements in the plug. At the other end, the conductive springs are connected with rotating fittings to the flat male electrical contacts.
During the manufacturing process, the springs and flat electrical contacts are positioned within one half of the plug so that the contacts are rotated to the rear when female plugs are required and to the front when male plugs are required. One half of the plug is then fused onto the other half.
U.S. Pat. No. 3,439,311 issued to Evans. This plug uses electrical contacts which are snaped to form a female receptacle on one end and a male contact on the other. The position in which the electrical contact is mounted within the plug determines the male or female character of the plug.
U.S. Pat. No. 4,010,993 issued to Hohenberger. A socket is formed by molding, and either a male or female element is inserted into place in the socket to complete the plug.
Still other patents change the character of the plug by inserting modules which lock into place and are then soldered or otherwise connected to electrical conductors through the end of the plug. Representative of this approach are U.S. Pat. No. 3,885,849 issued to Bailey, et al and U.S. Pat. No. 4,158,473 issued to Shearer.
As the plug art evolved, simplified mechanisms for attaching the electrical contacts of the plugs to wire conductors also evolved. A. C. Long, U.S. Pat. No. 3,083,344, A. C. Brown, U.S. Pat. No. 3,252,126, and R. M. Hohnenberger, U.S. Pat. No. 4,010,993 teach three approaches to soldered and quick-connect systems. Additional patents show that the industry has not only simplified its forming, assembly, and inventory, it has also tried to simplify the connection costs to reduce the ultimate assembly required from the user.
The present invention uses the improvements of the prior art to provide the low inventory costs and assembly costs required by the manufacturer and preserves the user's ability to convert gender. As such, it runs counter to the trends of the industry and provides a solution to many of industry's and user's problems. The inventions' various forms can be used in either the audio communication field, or the computer field. It can be metal sheathed for communication and computer usage purposes, and, as such, can have the usual male/female plug interlocks found in many military and communication industry plugs. Further, it can be adapted to be very lightweight for environments where shielding, dust resistance, water resistance, etc. are not required. Finally, it can use a variety of electrical contact cross-sections, i.e., those found in the various references described above.